My invention relates to a simplified electric lighting fixture using a standard voltage U-shaped fluorescent lamp designed for outdoor use and constructed mainly of polyvinyl chloride resin.
Until recently, for various reasons, most electric lighting fixture housings and fittings have been made of metal. One reason is that metals do not deteriorate or deform as the result of the high temperatures generated within the fixture by incandescent 110-volt lamps used in conventional lighting fixtures. However, for lighting fixtures designed for use out-of-doors, most metal housings and fittings are subject to rapid corrosion due to constant exposure to rain and sun and, in coastal areas, to salt spray, even when the metal parts are temporarily protected by paint. Recent increases in the price of metals and in fabricating costs have resulted in increases in the prices of conventional lighting fixtures with housings and fittings made of metal.
The present trend to reduce energy consumption has resulted in increased use of low voltage lamps; that is, incandescent lamps which operate at voltages considerably less than 110 volts. These low voltage lamps, particularly 12-volt incandescent lamps, generate far less heat in operation than 110-volt lamps.
My prior U.S. Pat. No. 4,564,890 disclosed an outdoor lighting fixture using a standard voltage U-shaped fluorescent lamp having ten major components as follows: a cylindrical housing having at its center an interior annular ring made of high density polyvinyl chloride resin (hereinafter often referred to as PVC); a U-shaped fluorescent lamp; a socket for the lamp; a circular base supporting the socket having an outer diameter less than the inside diameter of the cylindrical housing; a 120-volt transformer mounted on the base: a retaining ring having an outer diameter less than the inside diameter of the housing; a closed-ended tubular transparent diffuser having a diameter somewhat less than the inner diameter of the housing; a pair of flexible O-rings for securing the diffuser to the housing; and a circular bushing of PVC for sealing the rear of the housing and containing an annular opening for the electric wires connected to energize the U-shaped fluorescent lamp.
As mentioned in my aforesaid prior patent, there are a number of prior suggestions in the art to use various plastic and elastomeric resins in the fabrication of lighting fixture components. These suggestions include U.S. Pat. Nos. 3,902,057; 4,210,841; 4,360,862; 4,379,321; 4,380,793; 4,414,613; 4,523,263 and 4,564,890.
However, my simplified outdoor lighting fixture using a standard voltage U-shaped fluorescent lamp possesses the following advantages over previous outdoor fixtures.
1. Because it comprises only a few components and these components are already manufactured in quantity, the cost of its components is lower than the cost of conventional fixture components.
2. Because of the simplicity of its components which can be quickly assembled by unskilled labor, my lighting fixtures costs less to manufacture than conventional fixtures.
3. Because of its simple cylindrical form, my lighting fixture is more rugged and easier to disassemble than conventional fixtures.
My improved and simplified outdoor lighting fixture includes the following components: a cylindrical housing having at its center an interior annular ring; a U-shaped fluorescent lamp; a 120 volt transformer; a hollow cylindrical housing extension; a flat circular base plate; a dish-shaped reflector, two cylindrical spacer rings whose outer diameters are slightly smaller than the inner diameter of the cylindrical housing; a flat circular lens, and an elastomeric compressible O-ring. All these components are used in vast quantities in other fields and hence are readily available at modest cost.